The present invention relates to avionics devices and methods, and in particular to landing safety avionics.
Despite advances in flight safety technology, aircraft continue to encounter a phenomenon known as the xe2x80x9clast mile,xe2x80x9d wherein the pilots who have successfully overcome the obstacles presented by flight through congested airspace, storms, and terrain, crash during the last mile of flight. This is often the result of the pilot transitioning from flight by reference to instruments inside the cockpit to using visual scanning outside the cockpit, often as the result of a circling approach at night or in marginal visibility conditions. While dealing with these challenges, pilots often have to use experience and a well-developed sense of xe2x80x9cfeelxe2x80x9d for proper speed and glideslope management, especially at airfields lacking precision instrument approaches or visual glideslope indicators. An additional challenge is presented to those aircraft that have the benefits of many modern aircraft, yet lack the different complex sensor systems that might prevent mishaps such as landing short, long or fast. The advent and proliferation of Global Positioning System (GPS) technology represents a low-cost, low-technology solution to some of these problems, but is ineffective in eliminating the common xe2x80x9clast milexe2x80x9d hazards.
One commercial product, the Enhanced Ground Proximity Warning System(copyright) (EGPWS) available from Honeywell International, Incorporated of Redmond, Wash. provides excellent protection for aircraft in the en-route and terminal environments, especially for recent generation Air Transport category aircraft that already contain a wide range of complex sensors. However, despite the complex data concentration and collision avoidance algorithms of the EGPWS, crashes still occur during circling or visual approaches when the aircraft is within 1-2 miles of the intended runway and on a visual or non-precision approach. The protection provided by the EGPWS is restricted by the manner in which the terrain floor and step-down airspace limitations in the vicinity of the runway are computed. The EGPWS computations include assumptions that reduce terrain avoidance protection for aircraft within one mile of the runway. Such assumptions may leave insufficient protection during abnormal approaches, for example, when an ILS straight-in approach has not been established.
Also, although EGPWS can provide significant safety benefits to pilots in the approach phases, even in the systems designed for low-end general aviation aircraft may be prohibitively expensive for many small general aviation aircraft. The current installed cost of such a safety system is approximately ⅓ of the hull value of many of these piston aircraft, which makes installation of the equipment impractical. The result is that, although small piston aircraft have the highest incidence of landing accidents due to excessive sink rates, overshot landings, and runway misalignment, these aircraft are denied the benefits of modern safety avionics.
Thus, despite advances in the performance of safety avionics, the art still fails to specifically address the hazards associated with the final landing phase of flight.
The present invention is a warning system to compute, detect and display the exceeding of parameters such as descent angle, rate of descent, line-up, insufficient runway remaining after touchdown, and excessive energy on approach.
According to one aspect of the invention, the present invention provides a means for determining a terminal flight path correspondence or deviation, including: a means for receiving a plurality of navigation signals; a means for determining a current position as a function of the navigation signals; a means for determining an Intended Touchdown Point; a means for determining a Current Touchdown Point; a means for determining correspondence between the Current Touchdown Point and Intended Touchdown Point; and a means for outputting a signal representative of the correspondence between the Current Touchdown Point and Intended Touchdown Point.
According to another aspect of the invention, the means for determining a Current Touchdown Point also includes means for comparing subsequent navigation signals as a function of elapsed time between the subsequent navigation signals.
According to another aspect of the invention, the means for determining a Current Touchdown Point also includes determining a rate of descent.
According to another aspect of the invention, the means for determining a terminal flight path correspondence or deviation also includes a means for retrieving a runway altitude information from a database of airport information, and the means for determining a Current Touchdown Point includes determining an intersection with the runway.
According to another aspect of the invention, the means for determining a Intended Touchdown Point also includes a means for determining a glide path to the Intended Touchdown Point position, the means for determining a Current Touchdown Point includes a means for determining an actual glide path as a function of one or more of the navigation signals, and the means for determining correspondence between the Current Touchdown Point and Intended Touchdown Point includes a means for determining deviation of the actual glide path from the glide path to the Intended Touchdown Point position.
According to another aspect of the invention, the means for outputting a signal representative of the correspondence between the Current Touchdown Point and Intended Touchdown Point also includes a means for generating one or more of an audio and a video signal. The means for generating a video signal optionally includes means for generating one or more of a signal representative of a deviation of a forward Current Touchdown Point from the Intended Touchdown Point and a signal representative of a deviation of a lateral Current Touchdown Point from the Intended Touchdown Point. The means for determining a terminal flight path correspondence or deviation may also include means for displaying the video signal.
According to another aspect of the invention, the means for determining a terminal flight path correspondence or deviation includes a means for receiving a plurality of different aircraft data signals, and the means for determining a Current Touchdown Point includes a means for determining the Current Touchdown Point as a function of the aircraft data signals.
According to another aspect of the invention, the means for determining a terminal flight path correspondence or deviation includes a means for receiving a one or more data signals representative of atmospheric conditions, and the means for determining a Current Touchdown Point includes a means for determining the Current Touchdown Point as a function of the atmospheric data signals.
According to another aspect of the invention, the invention provides a terminal flight path deviation generator having: a stored database of airport runway location and elevation information accessible as a function of position; a processor coupled to receive aircraft position and elevation data and coupled for retrieving the airport information from the database as a function of the aircraft position data, the processor being structured to operate a computer program for generating a Current Touchdown Point position, comparing the Current Touchdown Point position to a predetermined Intended Touchdown Point position, and generating a signal representative of deviation of the Current Touchdown Point position from the predetermined Intended Touchdown Point position; and a cockpit warning indicator being coupled to receive the deviation signal and being structured to generate a warning as a function of the deviation signal.
According to another aspect of the invention, the processor portion of the terminal flight path deviation generator of the invention is further structured to operate a computer program for generating the Intended Touchdown Point position.
According to another aspect of the invention, the cockpit warning indicator portion of the terminal flight path deviation generator is an audio annunciation device, and a visual display device, or both.
According to another aspect of the invention, the processor portion of the terminal flight path deviation generator of the invention is further structured to operate a computer program for determining runway direction information. The processor portion is optionally further structured to operate a computer program for generating an ideal glideslope to the Intended Touchdown Point position and to operate a computer program for determining deviation of an actual track from the ideal glideslope to the Intended Touchdown Point position. According to another aspect of the invention, the cockpit warning indicator portion of the terminal flight path deviation generator of the invention is a visual display device having a horizontal display portion for indicating a lateral deviation of the Current Touchdown Point position from the Intended Touchdown Point position. Optionally, the cockpit visual display device includes a ladder indicator for indicating deviation of the Current Touchdown Point position from the Intended Touchdown Point position.
According to another aspect of the invention, the processor portion of the terminal flight path deviation generator of the invention is further coupled to receive aircraft performance data, and is further structured to operate a computer program for generating a Current Touchdown Point position as a function of the aircraft performance data.
According to yet another aspect of the invention, the invention provides a method for using an electronic circuit to compare a signal conveying Current Touchdown Point data with a predetermined Intended Touchdown Point, the method including: receiving a plurality of navigation signals; retrieving runway information from a database as a function of one or more of the navigation signals; determining a Current Touchdown Point relative to a runway as a function of the navigation signals; determining an Intended Touchdown Point relative to the runway as a function of the runway information; determining deviation of the Current Touchdown Point from the Intended Touchdown Point; and outputting a signal representative of the deviation of the Current Touchdown Point from the Intended Touchdown Point.
According to another aspect of the method of the invention, the method includes receiving a plurality of aircraft performance signals, and the portion of the method for determining a Current Touchdown Point includes determining the Current Touchdown Point as a function of the aircraft performance signals.
According to another aspect of the invention, the method additionally includes: determining a runway length; determining a safe stopping distance after the Intended Touchdown Point; determining deviation of the safe stopping distance and the runway length; and outputting a signal representative of the deviation of the safe stopping distance and the runway length.
According to another aspect of the invention, the method of the invention may include receiving a plurality of atmospheric condition signals, and determining the Current Touchdown Point as a function of the atmospheric condition signals.
According to another aspect of the method of the invention, determining deviation of the Current Touchdown Point from the Intended Touchdown Point includes determining both a forward and a lateral deviation of the Current Touchdown Point from the Intended Touchdown Point. Optionally, the method of the invention includes generating a display representative of both the forward and lateral deviations of the Current Touchdown Point from the Intended Touchdown Point. Optionally, determining an Intended Touchdown Point relative to the runway includes determining a preferred glide path, determining a Current Touchdown Point relative to the runway includes determining an actual glide path, and determining deviation the lateral deviation of the Current Touchdown Point from the Intended Touchdown Point includes determining deviation of the actual glide path from the preferred glide path.
According to another aspect of the invention, the invention is embodied in a computer program product for configuring an avionics device, the computer program product including a computer-usable medium having computer-readable code embodied therein for configuring a computer processor. The computer program product of the invention includes: computer-readable code configured to cause a computer processor to retrieve from storage on a computer-readable medium a set of airport information data; computer-readable code configured to cause a computer processor to determine an Intended Touchdown Point as a function of the airport information data; computer-readable code configured to cause a computer processor to access a set of aircraft position information; computer-readable code configured to cause a computer processor to determine a current aircraft position as a function of the set of aircraft position information; computer-readable code configured to cause a computer processor to determine a Current Touchdown Point as a function of the aircraft""s current position; and computer-readable code configured to cause a computer processor to determine a correspondence of the Current Touchdown Point and Intended Touchdown Point, and to generate an output signal as a function of the correspondence.
According to different aspects of the invention, the computer program product also includes computer-readable code configured to cause a computer processor to generate a real-time instantaneous correspondence indication as a function of the correspondence signal. The output signal generated as a function of the correspondence of the Current Touchdown Point and Intended Touchdown Point may include a warning indication signal generated as function of the real-time instantaneous correspondence exceeding a maximum permissible deviation.
According to another aspect of the invention, the computer program product includes computer-readable code configured to cause a computer processor to determine a current glide path as a function of a plurality of subsequent sets of aircraft position information. The computer program product also includes computer-readable code configured to cause a computer processor to determine a correspondence of the current glide path and a predetermined glide path and to generate an output signal as a function of the correspondence.
According to another aspect of the invention, the computer program product of the invention further includes computer-readable code configured to cause a computer processor to access a set of aircraft performance data; and the computer-readable code configured to cause a computer processor to determine the Current Touchdown Point includes computer-readable code configured to cause a computer processor to determine the Current Touchdown Point as a function of the aircraft performance data. The computer program product also includes computer-readable code configured to cause a computer processor to determine flightpath energy as a function of the aircraft performance data, and computer-readable code configured to cause a computer processor to determine a correspondence of the flightpath energy and the set of airport information data and to generate an output signal as a function of the correspondence.
According to another aspect of the invention, the computer program product also includes computer-readable code configured to cause a computer processor to access a set of current atmospheric data; and the computer-readable code configured to cause a computer processor to determine the Current Touchdown Point includes computer-readable code configured to cause a computer processor to determine a Current Touchdown Point as a function of the current atmospheric data.